#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
const int inf = 1000000001;
const ll INF = 2e18;
const ll MOD = 1000000007;
const ll mod = 1000000009;
const double pi = 3.14159265358979323846;
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };

const int K = 10010;
vll C(K, vl(K));


ll mod_pow(ll x, ll p, ll M) {
	ll a = 1;
	while (p) {
		if (p % 2)
			a = a*x%M;
		x = x*x%M;
		p /= 2;
	}
	return a;
}

ll mod_inverse(ll a, ll m) {
	return mod_pow(a, m - 2, m);
}

int main() {
	ll n, k;
	cin >> n >> k;
	C[0][0] = 1;
	rep1(i, k + 3) {
		rep(j, i + 1) {
			if (j == 0 || j == i) {
				C[i][j] == 0;
			}
			else {
				C[i][j] = (C[i][j - 1] + C[i][j]) % MOD;
			}
		}
	}
	vl bel(k + 1);
	bel[0] = 1;
	rep1(i, k + 1) {
		rep(j, i) {
			(bel[i] += C[i + 1][j] * bel[j] % MOD) %= MOD;
		}
		(bel[i] *= mod_inverse(-i - 1, MOD));
	}
	ll ans = 0;
	rep(i, k + 1) {
		(ans += C[k + 1][i] * bel[i] % MOD * mod_pow(n + 1, k + 1 - i, MOD) % MOD) %= MOD;
	}
	(ans *= mod_inverse(k + 1, MOD)) %= MOD;
	cout << ans << endl;
}